Wijnands Charissa, Karel Peter G A, Gloerich Jolein, Armony Gad, Tzasta Anastasia, de Kat Angelino Corrie M, Di Stefano Luciano, Bonifay Vincent, Luider Theo M, VanDuijn Martijn M, Croockewit Sandra J, de Kort Elizabeth A, Castelijn Daan A R, Stege Claudia A M, Wessels Hans J C T, van Gool Alain J, van de Donk Niels W C J, Jacobs Joannes F M
Laboratory Medical Immunology, Department of Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.
Laboratory of Clinical Chemistry, Deventer Ziekenhuis, 7416 SE Deventer, The Netherlands.
Pharmaceutics. 2025 Jan 19;17(1):135. doi: 10.3390/pharmaceutics17010135.
Multiple Myeloma (MM) is a hematologic malignancy caused by clonally expanded plasma cells that produce a monoclonal immunoglobulin (M-protein), a personalized biomarker. Recently, we developed an ultra-sensitive mass spectrometry method to quantify minimal residual disease (MS-MRD) by targeting unique M-protein peptides. Therapeutic antibodies (t-Abs), key in MM treatment, often lead to deep and long-lasting responses. However, t-Abs can significantly decrease the total polyclonal immunoglobulin (Ig) levels which require supplemental IgG infusion. Here, we demonstrate the simultaneous monitoring of M-proteins, t-Abs, and polyclonal Ig-titers using an untargeted mass spectrometry assay, offering a comprehensive view of therapy response. Sera collected between 2013 and 2024 from four patients and cerebrospinal fluid (CSF) from one patient who received various t-Abs were analyzed with MS-MRD. M-protein sequences were obtained with a multi-enzyme de novo protein sequencing approach. Unique peptides for M-proteins and t-Abs were selected based on linearity, sensitivity, and slope coefficient in serial dilutions. Ig constant regions were monitored using isotype-specific peptides. The MS-MRD multiplex analysis provided detailed information on drug concentrations and therapy response kinetics. For example, in two patients with refractory disease over five lines of therapy, the MS-MRD analysis showed that the deepest responses were achieved with bispecific t-Ab (teclistamab) treatment. M-protein and t-Ab were also detectable in the CSF of one patient with MS-MRD. This proof-of-concept study shows that the multiplex monitoring of the M-protein, any t-Ab combination, and all Ig-isotypes within one mass spectrometry run is feasible and provides unique insight into therapy response kinetics.
多发性骨髓瘤（MM）是一种血液系统恶性肿瘤，由克隆性扩增的浆细胞引起，这些浆细胞产生单克隆免疫球蛋白（M蛋白），这是一种个性化生物标志物。最近，我们开发了一种超灵敏质谱方法，通过靶向独特的M蛋白肽来定量微小残留病（MS-MRD）。治疗性抗体（t-Ab）是MM治疗的关键，通常会带来深度且持久的反应。然而，t-Ab会显著降低总多克隆免疫球蛋白（Ig）水平，这需要补充IgG输注。在此，我们展示了使用非靶向质谱分析同时监测M蛋白、t-Ab和多克隆Ig滴度，从而全面了解治疗反应。对2013年至2024年期间从4名患者收集的血清以及1名接受各种t-Ab治疗的患者的脑脊液（CSF）进行了MS-MRD分析。通过多酶从头蛋白质测序方法获得M蛋白序列。基于系列稀释中的线性、灵敏度和斜率系数选择M蛋白和t-Ab的独特肽段。使用同型特异性肽段监测Ig恒定区。MS-MRD多重分析提供了有关药物浓度和治疗反应动力学的详细信息。例如，在两名接受过五线以上治疗的难治性疾病患者中，MS-MRD分析表明，双特异性t-Ab（替雷利珠单抗）治疗取得了最深的反应。在一名有MS-MRD的患者的脑脊液中也检测到了M蛋白和t-Ab。这项概念验证研究表明，在一次质谱分析中对M蛋白、任何t-Ab组合以及所有Ig同型进行多重监测是可行的，并能为治疗反应动力学提供独特见解。
